1. Field of the Invention
The present invention relates to a shock absorber arrangement for mounting delicate equipment on a carrier such as a vessel or a vehicle in such a manner that the equipment is normally rigidly connected to the carrier in a predetermined position relative thereto, but is permitted to yield as a result of shocks involving an acceleration beyond a certain limit, whereupon it is forced back into said predetermined position.
The invention also relates to a shock absorber for use in such an arrangement.
When three-axes stabilized instruments such as navigation equipment comprising a gyro are mounted on board ships, it is important that the equipment when in use has an accurately defined postion with respect to the ship. However, when the equipment is completely rigidly mounted, it may suffer damage from shock loads, for instance due to an under-water explosion. It is therefore desirable to mount the equipment in such a manner that is is normally rigidly connected to the ship, but is permitted to yield as a result of shocks or vibrations of the ship involving an acceleration beyond a certain limit, thus protecting the equipment against excessive shock forces. This may be obtained by including a biased spring which releases the locking of the equipment in the desired position when the forces on the equipment exceed the biasing force. When the load is reduced the equipment should automatically and without excessive oscillations return to the desired predetermined position. This result may conveniently be obtained by means of mating conical surfaces which are forced into self-centering engagement with each other by means of the biased spring.
2. Description of the Prior Art
Thus, from German Auslegeschrift No. 1 578 306 it is known to mount a periscope tube in an annular housing on a vehicle. In the housing, which surrounds the periscope, there are mounted three circumferentially spaced spring-biased bolts extending parallel to the axis of the periscope column and having conical fitting and locking surfaces for engagement with three holes in a flange on the periscope column. The bolts are spring biased not only with respect to the housing but through a further spring also with respect to a second flange on the periscope column, whereby shocks can be absorbed in both directions along the axes of the bolts while compressing respective springs. Lateral forces are accommodated by compression of both springs by axial movement of the bolts due to a wedge effect against the conical locking surface. The bolts are mounted for axial movement in guide bores in the housing, and the accuracy of the position of the periscope tube in the housing in the noraml position thus depends on the fit between the guide bores and the bolts.
The object of the present invention is to provide a mounting of the kind initially referred to, which may be obtained by means of compact, light-weight and space-saving shock absorbers which are simple to mount and which in a simple manner may be arranged so as to absorb both vertical and horizontal shock loads.